Color photography.



M. .J. WOHL 8/: M. MAYER.

COLOR PHOTOGRAPHY. APPLICATION FILED ocT/fa. 191s Patented Dec. 29, 1914.

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M. J. WOHL & M. MAYER.

COLOR PHOTOGRAPHY. APPLICATION FILED 00T.15.1913.

m/VE/vmm M 771M A UNITED STATES PATENT Mansion J. WOHL, or nnooxtvn, AND MAX MAYER, or new roan, 1v. Y., ASSIGNOBS, BY MESNE ASSIGNMENTS, T0 renonnoiaotrron, Inc, a coaroaerion ornnw JERSEY.

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Specification of Letters Patent. Patented "Den. 29, 1%14,

Appiibation filed October 15, 1913. Serial 110.7%,244.

To all whom it mag concern: Be it known that we, Mannion J. WoHL, a citizen of the United States, and resident of the borough of Brooklyn, county of Kings, and State of New York, and MAX MAYER, a citizen of. the United States, and resident of the city, county, and State of New York, have invented .certain new and useful improvements in 'Color Photography, 9f which the following isa specification.

This invention relates to the art of pro ducing photographic pictures in naturalcolors and more particularly in its applica: tion inthe production of a film for use in a motion picture machine.

The object of the invention is to provide means for reproducing color values in negative, and in the projected positive, picture, more perfectly and completely than is possible with any other known methods.

In carrying out the invention we can either employ the principle of persistence-of vision or the superposing of different colors or color values.

Our improved method consists in the use of four diiferentcolor screens arranged in two sets, eachset being composed of balanced complementary colors different from the colors of the other set so that the four screens cover a much wider range of the spectrum than is possible with any two or threeqcolor combinations. A further purposeis served by this arrangement of avoiding the extreme amount of flicker, by reason of the fact that the color sensations produced byonc set of screens overlaps those of the other set, the second set extending tl. e sensations over a difierent section of the spectrum. If the spectrum were merely divided into four parts upon four screens and projected consecutively in the order of the spectrum, it would be necessary to maintain a very high speed in order to obtain the color effects by persistence of vision and, furthermore, as efny one of the colors, such as the bright red, would only occur in every fourth projection or picture, there would result an abnormal amount of flicker.

VVith our improved arrangement of the four color screens in sets, each set composed of balanced complementary colors, it is possible to distribute the color sensations in such a manner that the colors weakly pro-.

duced by either set of screens is strengthened by the corresponding stronger color of the other set and, at the same time, the range of the colors recorded is extended over practically the whole spectrum. These screens when used for producing motion picture negative films are arranged to be moved so that each set of screens impresses its color values upon one set of pictures, the two sets ofscreens impressing their .colorvalues upon four successive pictures. In the projection of the pictures the screens are correspondingly moved in front ofthe film and the entire range of colors covered by the four screens is thus reproduced in four succeeding pictures arranged in complementary sets or pairs. --The persistence of vision is sufliciently strong to cause the color sensations of the two sets of pictures to overlap and, on account of the arrangement of the screens above described, the colors are reproduced not only in a'wider range but with exceedingly soft graduations of tone and ab sence of flicker. This permits the screens to be made of greater luminosity and reduces the eye strain on account of the gradual blending of the colors.

Balanced colors are complementary colors of like photographic-density which produce duce white when combined, but which may be of unequal density, and usually are so. By the term balanced, we mean that when exposure on a panchromatic film is made through the balanced complementary colors for an equal length of time with a given intensity of light, the records of white objects give an equal intensity ofimage.

The colors for each set of screens are complementary and are made to balance. These colors are determined by dividing the spectrum into substantially four parts and forming the first set of screens from the first and third parts and the second set of screens from the second and fourth parts of the spectrum so divided. Each set of screens will thus make some record of every color value but the record or color value given by each set of screens will be difierent. The true color value is then obtained in the persistence of vision method when the four successive pictures have followed each other I in the same order, one color for each succeeding picture.

Second ;v by presenting the two colors corresponding to first and third pictures of the negative for the first positive picture, the colors corresponding to the second and fourth negative pictures being presented for the second positive picture, the colors of the first and third negative pictures for the third positive picture and those of the sec-- ond. and fourth negative pictures for the fourth positive picture, following always in this cycle, viz, two adjacent colors for each succeeding positive view. In this mannor the color sensations recorded differently by each set of colors in photographing is averaged in the projection.

Third; by presenting alternately the four color value pictures through a two color screen only,-one color serving the odd number of the positive series picture, the other color serving the even numbers each projecting screen having its colors 0 osen from a combination of the set of colors used in the taking screens. In the latter case, although the four colore'd' positive is only served by a two color screen, the extended range of color impressions gathered by the four colored negativeois to a large extent reproduced by the color projection screen, when the latter has its colors chosen for this purpose, each projecting screen being composed of a color which is a combination of the first color in each set in the one case, and the second colors in each set in the second case.

Figures 1 and 2 of the drawings show an optical synthesis of the spectrum, the colors being arranged for the purpose of illustration and comparison in the form of a complete circle. The color sensations as recorded by the two color process are shown in Fig. 1 and our improved process in Fig. 2. Semi-circular wedges are employed to 1IlCl1C1t(-)tll6 color sensatlons as recorded by the two processes and colors diametrically opposite each other are-complementary. In Fig. l, wedges a and b approximately record the color impressions produced by the two color process employing two-color screens 1 (red-orange) and 2- (blue-green), the range extending approximately from R (red) to C. B. (cyanblue). It will be noted that between U. B. (tilt-blue) and R (red) the records are al-. most entirely absent. In our improved process, Fig. 2, the two pairs or sets of elements are indicated by the wedges c d and e 7", the color screens being represented on the first set of elements as 1 (red) and 2 (green-blue) and in the second set of elements as 3 (yellow-orange) and 4: (violet-blue), the total range of color impressions approximately covered being from Red to Red, or practically the whole spec trum. It will be seen in Fig. 2 that the two sets of elements employed in our system overlap each other, and one set reinforces the weaker reproductions of the other.

Fig. 3 shows the application of the four color screens to the succeeding images on the film when making the negative, allowance being made in all cases for 30 images per second, A is the revolving color screen turning 74; revolutions per second and hav ing four color screens, for example 1 (red) 2 (green-blue) 3 (orange-yellow) and-4 (violet-blue), screens 1, 2, 3 and 4, synchronize with the order of the pictures shown at B, 1*, 2 3 and 4 In the exhibition or projection by persistence of vision three combinations of v pictures and screens may be employed, as

follows First; as shown in Fig. 3, viz, one color for each succeeding picture, the shutter revolving 7?; times per-second for 30 pictures per second exhibited.

Second; Fig. 4 shows the color screens C revolving at 15 per second, 1 and 2 screens serve (one after the other) the first picture of the film D, marked 1 and 2, the screens 3 and 4 serve (one after the other) the second picture onthe film D marked 3 and 4 the revolving color screen having made one complete revolution for these two first pictures. In the second revolution pictures 0 and d are served in the same manner, viz, two color screens for one picture.

Third; in Fig. 5 the color screenE revolving at 15' per second is composed of.

two colors only, 1 and 2, the first color' serves the first picture of film F, marked 1", the second color serves the second picture 2", then the first screen again comes into operation and serves the third'picture marked 1', and the second screen serves the fourth picture marked 2, and so on, viz, the first screen for all the odd numbers and the second screen for all the even pictures.

What we'claim is:-

1. A screen adapted for use with mechanism for producing color pictures in motion, said screen comprising the combination of a. series of four color screens arrangedin two dissimilar sets, each set being composed of screens of balanced complementary colors, the colors-of the one set overlapping those of the other set and extending over a different section of the spectrum.

2. A screen adapted for use with a single objective mechanism for producing motionpictures in color, said screen consisting of the combination of two dissimilar sets of complementary colors, the first set alternating with the secondset when the screen is operated before the single objective.

3. In motion picture photography,, the combination With a single. objective camera for making natural color pictures, of a plurality of different sets of screens each composed of balanced complementary colors, means for bringing said sets of screens successively before the single objective for making a series of succeeding images recording the different color impressions of the said screens.

4.. A movable color shutter consisting of four differently colored screens arranged and adapted, when used with a camera for taking natural color pictures, to follow con color impressions not correctly or entirely covered by the other set.

5. A'screen adapted for use With a machine for producing color pictures in motion, which consists of two pairs of balanced complementary colors, substantially red and green in one pair and orange and blue in the other pair, one color being used for each image recorded on the film through a single objective.

6. A color screen or filter comprising two sets of balanced complementary color screens, the colors being arranged in a single screen and adapted to be brought in 'front of a single objective successively.

Signed at Brooklyn, 'N. Y., in the county of Kings, State of New York, this 10th day of October, 1913/ MAURICE J. WOHL. lVlAX IVIAYER. Witnesses:

C. H. Mnnnrrr, JAMES M. HARRISON. 

